Post-resonance circuits, devices, systems, and methods

Abstract

Illustrative embodiments of high-resolution, low-loss phase shifting circuits, devices, systems, and methods are disclosed. According to one aspect, a circuit may include a signal reflector that has a signal port configured to receive a signal in a signal frequency range and a resonant structure coupled between the signal port and ground. The resonant structure has one or more primary resonant frequencies and a cutoff frequency above the one or more primary resonant frequencies. The cutoff frequency is below the signal frequency range of the signal applied to the signal port.

1 . A circuit comprising:
 a first signal reflector comprising:   a first signal port configured to receive a signal in a signal frequency range used for communication or computation; and   a first resonant structure coupled between the first signal port and ground, the first resonant structure having (i) one or more primary resonances that interact to form one or more hybrid resonances and (ii) a cutoff frequency above resonant frequencies of the primary and hybrid resonances, wherein the cutoff frequency is below the signal frequency range.   
     
     
         2 . The circuit of  claim 1 , wherein the first resonant structure is tunable to adjust the resonant frequencies. 
     
     
         3 . The circuit of  claim 2 , wherein the first resonant structure comprises a segmented waveguide and tunable capacitances coupling each junction of the segmented waveguide to ground. 
     
     
         4 . The circuit of  claim 3 , wherein each segmented waveguide includes at least three waveguide segments. 
     
     
         5 . The circuit of  claim 4 , wherein each junction of the segmented waveguide is coupled to ground by a programmable capacitor bank comprising a plurality of parallel legs coupled between one junction of the segmented waveguide and ground, each of the plurality of parallel legs comprising a capacitor and a switch coupled in series. 
     
     
         6 . The circuit of  claim 3 , wherein each tunable capacitance is digitally programmable. 
     
     
         7 . The circuit of  claim 3 , further comprising vacatur diodes configured to tune the tunable capacitances. 
     
     
         8 . The circuit of  claim 3  implemented as an integrated circuit such that the first signal reflector has a sub-wavelength footprint. 
     
     
         9 . The circuit of  claim 8 , wherein the segmented waveguide is formed as a conductive trace in an upper layer of the integrated circuit, and wherein each tunable capacitance is formed in lower layers of the integrated circuit. 
     
     
         10 . The circuit of  claim 1 , further comprising:
 a second signal reflector comprising (i) a second signal port configured to receive the signal in the signal frequency range and (ii) a second resonant structure coupled between the second signal port and ground, the second resonant structure having (i) one or more primary resonances that interact to form one or more hybrid resonances and (ii) a cutoff frequency above resonant frequencies of the primary and hybrid resonances, wherein the cutoff frequency is below the signal frequency range; and   a hybrid coupler having (i) an input port configured to receive the signal in the signal frequency range, (ii) a coupled port connected to the first signal port of the first signal reflector, (iii) a through port connected to the second signal port of the second signal reflector, and (iv) an output port configured to provide a phase-shifted copy of the signal.   
     
     
         11 . The circuit of  claim 10 , wherein an amount of phase shift between the signal and the phase-shifted copy of the signal is controllable in increments of less than 1 degree with less than 10 dB of loss. 
     
     
         12 . The phase shifter of  claim 10 , wherein an amount of phase shift between the signal and the phase-shifted copy of the signal is controllable in increments of less than 0.2 degrees with less than 5 dB of loss. 
     
     
         13 . The phase shifter of  claim 10 , wherein the first signal reflector, the second signal reflector, and the hybrid coupler do not consume DC power. 
     
     
         14 . The circuit of  claim 10  implemented as an integrated circuit such that the first signal reflector, the second signal reflector, and the hybrid coupler have a sub-wavelength footprint. 
     
     
         15 . A method comprising:
 tuning resonant frequencies of a resonant structure coupled between a signal port and ground, wherein the resonant frequencies are associated with one or more primary resonances of the resonant structure that interact to form one or more hybrid resonances, and wherein the resonant structure has a cutoff frequency above the resonant frequencies; and   applying, to the signal port, a communication or computation input signal having a signal frequency above the cutoff frequency; and   receiving, at the signal port, a reflected signal with a phase shift relative to the communication or computation input signal, wherein the phase shift is a function of the resonant frequencies of the resonant structure.   
     
     
         16 . The method of  claim 10 , wherein the resonant frequencies of the resonant structure are tunable to adjust the phase shift in increments of less than 1 degree with less than 10 dB of loss between the communication or computation input signal and the reflected signal. 
     
     
         17 . The method of  claim 10 , wherein the resonant frequencies of the resonant structure are tunable to adjust the phase shift in increments of less than 0.2 degrees with less than 5 dB of loss between the communication or computation input signal and the reflected signal. 
     
     
         18 . The method of  claim 10 , wherein the resonant structure comprises a segmented waveguide and tunable capacitances coupling each junction of the segmented waveguide to ground, and wherein tuning the resonant frequencies of the resonant structure comprises tuning one or more of the tunable capacitances. 
     
     
         19 . The method of  claim 18 , wherein each of the tunable capacitances comprises a plurality of parallel legs coupled between one junction of the segmented waveguide and ground, each of the plurality of parallel legs comprising a capacitor and a switch coupled in series, and wherein tuning one or more of the tunable capacitances comprises switching one or more switches of the plurality of parallel legs. 
     
     
         20 . The method of  claim 18 , wherein tuning one or more of the tunable capacitances comprises controlling one or more varactor diodes.